Redox Replacement of Silver on MOF‐Derived Cu/C Nanoparticles on Gas Diffusion Electrodes for Electrocatalytic CO2 Reduction. Issue 12 (2nd February 2022)

• Record Type: Journal Article
• Authors: Sikdar, Nivedita; Junqueira, João R. C.; Öhl, Denis; Dieckhöfer, Stefan; Quast, Thomas; Braun, Michael; Aiyappa, Harshitha B.; Seisel, Sabine; Andronescu, Corina; Schuhmann, Wolfgang
• Is Part Of: Chemistry. Volume 28:Issue 12(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-02-02
• Subjects: cascade reactions -- CO2 reduction -- electrocatalysis -- in-situ Raman spectroscopy -- redox replacement; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202104249
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Bimetallic tandem catalysts have emerged as a promising strategy to locally increase the CO flux during electrochemical CO2 reduction, so as to maximize the rate of conversion to C−C‐coupled products. Considering this, a novel Cu/C−Ag nanostructured catalyst has been prepared by a redox replacement process, in which the ratio of the two metals can be tuned by the replacement time. An optimum Cu/Ag composition with similarly sized particles showed the highest CO2 conversion to C2+ products compared to non‐Ag‐modified gas‐diffusion electrodes. Gas chromatography and in‐situ Raman measurements in a CO2 gas diffusion cell suggest the formation of top‐bound linear adsorbed *CO followed by consumption of CO in the successive cascade steps, as evidenced by the increasing ν C−H bands. These findings suggest that two mechanisms operate simultaneously towards the production of HCO2 H and C−C‐coupled products on the Cu/Ag bimetallic surface. Abstract : From CO2 to C2+ : A novel Cu/C−Ag nanostructured catalyst has been synthesized by electroless redox replacement directly on gas‐diffusion electrodes. An optimum Cu/Ag composition with similar‐sized nanoparticles showed the highest conversion of CO2 to C2+ products compared to only Cu‐modified gas diffusion electrodes. In‐situ Raman spectroscopy and gas chromatography measurements suggest two parallel CO2 reduction mechanisms to produce HCO2 H and C2+ products on the bimetallic Cu/Ag surface.